This invention relates to an eye protection device that can be used, for example, in a welding protective mask.
Eye protection devices are known in which an auto-darkening filter (ADF), typically comprising a liquid crystal cell, is driven from an undarkened state to a darkened state that protects a user's eyes from a welding flash or the like. FIG. 1 shows a timing chart of such an operation in a conventional eye protection device. The ADF starts in an undarkened state, and then is driven to a darkened state at time T1, upon detection of welding activity. A darkened state (either constant or varied) is maintained until time T2, at which welding activity is no longer detected (e.g., when an electric welding arc goes off). Thereafter, after a predetermined delay of from about 200 to about 500 milliseconds, the ADF returns very quickly to the undarkened state over the period of T3 to T4, a time of from about 2 milliseconds to about 5 milliseconds.